Pre-lithiation method of negative electrode for lithium secondary battery, negative electrode for lithium secondary battery, and lithium secondary battery comprising negative electrode

Abstract

The present application relates to a pre-lithiation method of a negative electrode for a lithium secondary battery, a negative electrode for a lithium secondary battery, and a lithium secondary battery including a negative electrode. The pre-lithiation method includes forming a negative electrode current collector layer and a negative electrode active material layer on one surface or both surfaces of the negative electrode current collector layer; forming a silver (Ag)-containing metal layer on a surface of the negative electrode active material layer opposite to a surface of the negative electrode active material layer facing the negative electrode current collector layer; and transferring lithium metal to a surface of the Ag-containing metal layer opposite to a surface of the metal layer facing the negative electrode active material layer. A thickness of the Ag-containing metal layer is 10 nm or greater and 2 μm or less.

1 . A pre-lithiation method of a negative electrode for a lithium secondary battery, the pre-lithiation method comprising:
 forming a negative electrode current collector layer and a negative electrode active material layer on one surface or both surfaces of the negative electrode current collector layer;   forming a silver (Ag)-containing metal layer on a surface of the negative electrode active material layer opposite to a surface of the negative electrode active material layer facing the negative electrode current collector layer; and   transferring lithium metal to a surface of the Ag-containing metal layer opposite to a surface of the metal layer facing the negative electrode active material layer,   wherein a thickness of the Ag-containing metal layer is 10 nm or greater and 2 μm or less.   
     
     
         2 . The pre-lithiation method of a negative electrode for a lithium secondary battery of  claim 1 , wherein the step of forming of the negative electrode current collector layer and the negative electrode active material layer on one surface or both surfaces of the negative electrode current collector layer comprises coating a negative electrode slurry comprising a negative electrode active material layer composition on one surface or both surfaces of the negative electrode current collector layer, and
 wherein the negative electrode active material layer composition comprises at least one or more selected from the group consisting of a silicon-containing active material, a negative electrode conductive material, and a negative electrode binder.   
     
     
         3 . The pre-lithiation method of  claim 1 , wherein the forming of the silver (Ag)containing metal layer on a surface of the negative electrode active material laver opposite to a surface of the negative electrode active material layer facing the negative electrode current collector layer comprises depositing the silver (Ag) on the negative electrode active material layer by physical vapor deposition (PVD). 
     
     
         4 . The pre-lithiation method of  claim 1 , further comprising: after transferring the lithium metal to the surface of the Ag-containing metal layer opposite to the surface of the Ag-containing metal layer facing the negative electrode active material layer, activating the lithium metal,
 wherein in the activating of the lithium metal, an activation reaction occurs within 30 minutes to 3 hours under conditions of 25° C. and 1 atm.   
     
     
         5 . The pre-lithiation method of  claim 1 , wherein the transferring of lithium metal to the surface of the Ao-containing metal layer opposite to the surface of the metal layer facing the negative electrode active material layer comprises:
 preparing a laminated body for transfer comprising a base layer and lithium metal on the base layer,   laminating the laminated body for transfer on the metal layer wherein a surface opposite to a surface of the lithium metal facing the base layer comes into contact with the surface opposite to the surface of the metal layer facing the negative electrode active material layer, and   removing the base layer.   
     
     
         6 . The pre-lithiation method of  claim 5 , wherein a release layer is further present between the base layer and lithium metal of the laminated body for transfer. 
     
     
         7 . The pre-lithiation of  claim 2 , wherein the silicon-containing active material comprises at least one selected from the group consisting of SiOx, wherein x=0, SiOx, wherein 0<x<2, SiC, and a Si alloy. 
     
     
         8 . The pre-lithiation method of  claim 2 , wherein the silicon-containing active material comprises at least one selected from the group consisting of SiOx, wherein x=0and SiOx, wherein 0<x<2, and comprises 70 parts by weight or more of the SiOx, wherein x=0 based on 100 parts by weight of the silicon-containing active material. 
     
     
         9 . The pre-lithiation method of  claim 1 , wherein a thickness of the lithium metal is 1 μm or greater and 10 μm or less. 
     
     
         10 . A negative electrode for a lithium secondary battery comprising:
 a negative electrode current collector layer;   a negative electrode active material layer comprising a negative electrode active material layer composition on one surface or both surfaces of the negative electrode current collector layer; and   a silver (Ag)containing metal layer provided on a surface opposite to a surface of the negative electrode active material layer facing the negative electrode current collector layer,   wherein a thickness of the Ag-containing metal layer is 10 nm or greater and 2 μm or less.   
     
     
         11 . The negative electrode for a lithium secondary battery of  claim 10 , wherein a thickness of the negative electrode current collector layer is 1 μm or greater and 100 μm or less, and
 wherein a thickness of the negative electrode active material layer is 20 μm or greater and 500 μm or less. 
 
     
     
         12 . A lithium secondary battery comprising:
 a positive electrode;   a negative electrode for a lithium secondary battery pre-lithiated according to the pre-lithiation method of  claim 1 ;   a separator between the positive electrode and the negative electrode; and   an electrolyte solution.